1. Field of the Invention
The present invention relates to an airbag, and more particularly, to an airbag device for a vehicle capable of performing a rapid deploying operation at the time of initially deploying an airbag cushion and exhibiting appropriate buffering performance at the time of loading a passenger, and also improving deploying performance of the airbag cushion by increasing operability of a tether.
2. Description of Related Art
Since an airbag buffers a shock of the passengers by an appropriate inflation of an airbag cushion in case of accident of a vehicle to thereby reduce or prevent injury of the passengers, an inflation behavior of the airbag cushion plays an important role in securing safety of the passengers.
Particularly, the required inflation behavior of the airbag cushion should rapidly constrain the passengers by a rapid inflation upon an initial deploying operation of the airbag cushion and may appropriately buffer the passengers by appropriately discharging an expanding gas in the airbag cushion upon a loading at which the passenger is in contact with the airbag cushion and applies his/her load to the airbag cushion.
In addition, for example, requirements required from various regulations such as low risk deployment (LRD) regulations of North America, and the like should be satisfied. In case of the LRD regulations, it is required to minimize an injury of children or the passengers positioned in the vicinity of an airbag device by allowing the expanding gas to be discharged through a vent hole even at the time of the initial deploying operation of the airbag cushion and hereinafter, performance for satisfying the above-mentioned LRD regulations is referred to as LRD performance.
However, in order to satisfy the LRD performance as described above, even at the time of the initial deploying operation of the airbag cushion, the vent hole of the airbag cushion should be opened so that a portion of the expanding gas may be discharged, the vent hole should be closed at the time of the initial deploying operation of the airbag cushion, if possible, in order to rapidly expand the airbag cushion as described above, and the vent hold should be opened to allow the expanding gas to be discharged once the airbag cushion is fully deployed and the passenger starts to be loaded. As described above, it was difficult to implement the vent hole so as to be appropriately opened or closed at an appropriate timing depending on a progress of the deploying process of the airbag cushion and seating conditions of the passenger.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.